ASTM B540-21

Standard Specification for Palladium Electrical Contact Alloy

ABSTRACT
This specification covers an alloy containing palladium, silver, copper, gold, platinum, and zinc in the form of wire, rod, and strip for electrical contacts. The material shall be finished by such operations: cold working, heat treating, annealing, turning, grinding, and pickling. Material shall meet the requirements of chemical composition as specified. Knoop hardness test and tension test shall be made to conform to the specified requirements. Chemical analysis shall be performed by spectrochemical or wet analysis methods.
SCOPE
1.1 This specification covers an alloy containing palladium, silver, copper, gold, platinum, and zinc in the form of wire, rod, and strip for electrical contacts.  
1.2 The values stated in inch-pound units are to be regarded as standard. The values given in parentheses are mathematical conversions to SI units that are provided for information only and are not considered standard.  
1.3 It is the responsibility of the user to become familiar with all hazards including those identified in the appropriate Safety Data Sheet (SDS) for this product/material as provided by the manufacturer.  
1.4 The following safety hazard caveat pertains only to the test methods portion, Section 6 of this specification. This standard does not purport to address all of the safety concerns, if any, associated with its use. It is the responsibility of the user of this standard to become familiar with all hazards including those identified in the appropriate Safety Data Sheet (SDS) for this product/material as provided by the manufacturer, to establish appropriate safety, health, and environmental practices, and determine the applicability of regulatory limitations prior to use.  
1.5 This international standard was developed in accordance with internationally recognized principles on standardization established in the Decision on Principles for the Development of International Standards, Guides and Recommendations issued by the World Trade Organization Technical Barriers to Trade (TBT) Committee.

General Information

• Status: Published
• Publication Date: 31-Oct-2021
• ICS: 77.120.99 - Other non-ferrous metals and their alloys
• Technical Committee: B02 - Nonferrous Metals and Alloys
• Drafting Committee: B02.05 - Precious Metals and Electrical Contact Materials and Test Methods

Relations

• Refers: ASTM E8/E8M-24 - Standard Test Methods for Tension Testing of Metallic Materials
• Effective Date: 01-Jan-2024
• Refers: ASTM E8/E8M-16 - Standard Test Methods for Tension Testing of Metallic Materials
• Effective Date: 15-Jul-2016
• Refers: ASTM E8/E8M-15 - Standard Test Methods for Tension Testing of Metallic Materials
• Effective Date: 01-Feb-2015
• Refers: ASTM E8/E8M-13 - Standard Test Methods for Tension Testing of Metallic Materials
• Effective Date: 01-Jun-2013
• Refers: ASTM B476-01(2012) - Standard Specification for General Requirements for Wrought Precious Metal Electrical Contact Materials
• Effective Date: 01-May-2012
• Refers: ASTM E8/E8M-11 - Standard Test Methods for Tension Testing of Metallic Materials
• Effective Date: 01-Dec-2011
• Refers: ASTM E384-10e1 - Standard Test Method for Knoop and Vickers Hardness of Materials
• Effective Date: 01-Feb-2010
• Refers: ASTM E384-10 - Standard Test Method for Microindentation Hardness of Materials
• Effective Date: 01-Feb-2010
• Refers: ASTM E384-09 - Standard Test Method for Microindentation Hardness of Materials
• Effective Date: 01-May-2009
• Refers: ASTM E384-08ae1 - Standard Test Method for Microindentation Hardness of Materials
• Effective Date: 15-Mar-2008
• Refers: ASTM E384-08a - Standard Test Method for Microindentation Hardness of Materials
• Effective Date: 15-Mar-2008
• Refers: ASTM E384-08 - Standard Test Method for Microindentation Hardness of Materials
• Effective Date: 01-Jan-2008
• Refers: ASTM E384-07a - Standard Test Method for Microindentation Hardness of Materials
• Effective Date: 15-Dec-2007
• Refers: ASTM E384-07 - Standard Test Method for Microindentation Hardness of Materials
• Effective Date: 01-Jul-2007
• Refers: ASTM E384-06 - Standard Test Method for Microindentation Hardness of Materials
• Effective Date: 15-Nov-2006

Overview

ASTM B540-21: Standard Specification for Palladium Electrical Contact Alloy defines requirements for an alloy composed of palladium, silver, copper, gold, platinum, and zinc. The standard covers forms such as wire, rod, and strip intended for use in electrical contacts. ASTM B540-21 outlines the permissible chemical composition, required mechanical properties, manufacturing processes, inspection, and testing criteria to ensure high performance and reliability in demanding electrical applications.

Adherence to ASTM B540-21 ensures consistency, durability, and optimal conductivity in precious metal electrical contact materials. This specification was developed in alignment with internationally recognized principles of standardization, facilitating global trade and quality assurance.

Key Topics

ASTM B540-21 addresses several critical aspects for palladium electrical contact alloys:

• Material Composition: Specifies stringently controlled percentages of palladium, silver, copper, gold, platinum, and zinc, with maximum limits on total platinum group and base metal impurities.
• Product Forms: Applies to wire, rod, and strip products, supporting various electrical contact manufacturing requirements.
• Manufacturing Processes: Requires operations such as cold working, heat treating, annealing, turning, grinding, and pickling to achieve desired material properties.
• Mechanical Properties: Details required tensile strength, elongation, and microhardness (tested via Knoop or Vickers methods) for different tempers and product dimensions.
• Testing Requirements: Mandates visual inspection, tension testing, hardness testing, dimensional checks, and chemical analysis to verify compliance.
• Safety Considerations: Emphasizes user familiarity with relevant Safety Data Sheets (SDS) and the necessity of maintaining proper safety, health, and environmental practices.

Applications

The palladium electrical contact alloy specified by ASTM B540-21 is widely used in:

• Electrical Connectors: Reliable in high-precision connectors found in telecommunications, aerospace, and defense industries.
• Switch Contacts: Provides excellent resistance to wear and corrosion, critical for switches that require consistent performance.
• Relay Components: Offers superior conductivity and durability, supporting relays in complex control systems.
• Electronic Contacts: Essential for critical electronic components where stable low-resistance contacts are necessary.

Key benefits of using materials compliant with ASTM B540-21 include:

• Enhanced electrical conductivity and low contact resistance
• High corrosion and tarnish resistance, especially in harsh or demanding environments
• Consistent mechanical performance across various forms and sizes
• Long-term durability and stability, reducing maintenance and replacement costs

Related Standards

For comprehensive material selection and compliance, the following related ASTM standards should be considered:

• ASTM B476: General Requirements for Wrought Precious Metal Electrical Contact Materials
• ASTM E8/E8M: Test Methods for Tension Testing of Metallic Materials
• ASTM E384: Test Method for Microindentation Hardness of Materials

These referenced standards ensure a cohesive framework for testing, procurement, and performance verification of precious metal electrical contact alloys.

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Implementing ASTM B540-21 in procurement and manufacturing guarantees high-quality, standardized electrical contact materials, supporting safety and efficiency in critical electrical and electronic applications. For the most up-to-date requirements and details, always reference the latest published standard from ASTM International.

Standards Content (Sample)

This international standard was developed in accordance with internationally recognized principles on standardization established in the Decision on Principles for the
Development of International Standards, Guides and Recommendations issued by the World Trade Organization Technical Barriers to Trade (TBT) Committee.
Designation:B540 −21
Standard Specification for
Palladium Electrical Contact Alloy
This standard is issued under the fixed designation B540; the number immediately following the designation indicates the year of
original adoption or, in the case of revision, the year of last revision.Anumber in parentheses indicates the year of last reapproval.A
superscript epsilon (´) indicates an editorial change since the last revision or reapproval.
This standard has been approved for use by agencies of the U.S. Department of Defense.
1. Scope B476Specification for General Requirements for Wrought
Precious Metal Electrical Contact Materials
1.1 This specification covers an alloy containing palladium,
E8/E8MTest Methods for Tension Testing of Metallic Ma-
silver,copper,gold,platinum,andzincintheformofwire,rod,
terials
and strip for electrical contacts.
E384Test Method for Microindentation Hardness of Mate-
1.2 The values stated in inch-pound units are to be regarded
rials
as standard. The values given in parentheses are mathematical
conversions to SI units that are provided for information only
3. Materials and Manufacture
and are not considered standard.
3.1 Raw materials shall be of such quality and purity that
1.3 It is the responsibility of the user to become familiar
thefinishedproductwillhavethepropertiesandcharacteristics
with all hazards including those identified in the appropriate
prescribed in this specification.
Safety Data Sheet (SDS) for this product/material as provided
3.2 The material shall be finished by such operations (cold
by the manufacturer.
working, heat treating, annealing, turning, grinding, pickling)
1.4 The following safety hazard caveat pertains only to the
as are required to produce the prescribed properties.
test methods portion, Section 6 of this specification. This
standard does not purport to address all of the safety concerns, 4. Chemical Composition
if any, associated with its use. It is the responsibility of the user
4.1 Materialproducedunderthespecificationshallmeetthe
of this standard to become familiar with all hazards including
requirements of chemical composition shown in Table 1.
those identified in the appropriate Safety Data Sheet (SDS) for
this product/material as provided by the manufacturer, to
5. Mechanical Properties
establish appropriate safety, health, and environmental
5.1 The contract or order may specify ultimate tensile
practices, and determine the applicability of regulatory limi-
strength, elongation, microhardness (Knoop or Vickers), or a
tations prior to use.
combination of these mechanical properties (as listed in Table
1.5 This international standard was developed in accor-
2, Table 3, and Table 4) as temper criterion. If the contract or
dance with internationally recognized principles on standard-
order does not specify a temper criterion, then the criterion for
ization established in the Decision on Principles for the
temper designation will be ultimate tensile strength and elon-
Development of International Standards, Guides and Recom-
gation.
mendations issued by the World Trade Organization Technical
5.1.1 Fully age-hardened temper is also known as heat-
Barriers to Trade (TBT) Committee.
treated age-hardened or as age-hardened.
5.1.2 Partially age-hardened temper (where higher material
2. Referenced Documents
ductility is retained due to either lower temperature or time of
2.1 ASTM Standards:
aging, or both) is also known as ductile heat-treated age-
hardened or as ductile-hardened.
6. Test Methods
This specification is under the jurisdiction of ASTM Committee B02 on
Nonferrous Metals and Alloys and is the direct responsibility of Subcommittee
6.1 Test methods shall be in accordance with Specification
B02.05 on Precious Metals and Electrical Contact Materials.
B476.
Current edition approved Nov. 1, 2021. Published December 2021. Originally
6.1.1 Knoop hardness tests shall be in accordance with Test
approved in 1970. Last previous edition approved in 2017 as B540–97(2017).
DOI: 10.1520/B0540-21.
Method E384. Material 0.005 in. (0.13 mm) in thickness
For referenced ASTM standards, visit the ASTM website, www.astm.org, or
(diameter) and larger shall be tested using a 100-g indenter
contact ASTM Customer Service at [e-mail]. For Annual Book of ASTM
load. Material less than 0.005 in. (0.13 mm) in thickness
Standards volume information, refer to the standard’s Document Summary page on
the ASTM website. (diameter) shall be tested using a 50-g indenter load. A
Copyright © ASTM International, 100 Barr Harbor Drive, PO Box C700, West Conshohocken, PA 19428-2959. United States
B540−21
TABLE 1 Chemical Requirements
Composition,
Element
weight %
Palladium 34.0–36.0
Silver 29.0–31.0
Copper 13.5–14.5
Gold 9.5–10.5
Platinum 9.5–10.5
Zinc 0.8–1.2
Total platinum group metal impurities 0.1 max
(iridium, osmium, rhodium, ruthenium)
Total base metal impurities 0.2 max
A
TABLE 2 Mechanical Proper
...

This document is not an ASTM standard and is intended only to provide the user of an ASTM standard an indication of what changes have been made to the previous version. Because
it may not be technically possible to adequately depict all changes accurately, ASTM recommends that users consult prior editions as appropriate. In all cases only the current version
of the standard as published by ASTM is to be considered the official document.
Designation: B540 − 97 (Reapproved 2017) B540 − 21
Standard Specification for
Palladium Electrical Contact Alloy
This standard is issued under the fixed designation B540; the number immediately following the designation indicates the year of
original adoption or, in the case of revision, the year of last revision. A number in parentheses indicates the year of last reapproval. A
superscript epsilon (´) indicates an editorial change since the last revision or reapproval.
This standard has been approved for use by agencies of the U.S. Department of Defense.
1. Scope
1.1 This specification covers an alloy containing palladium, silver, copper, gold, platinum, and zinc in the form of wire, rod, and
strip for electrical contacts.
1.2 The values stated in inch-pound units are to be regarded as standard. The values given in parentheses are mathematical
conversions to SI units that are provided for information only and are not considered standard.
1.3 It is the responsibility of the user to become familiar with all hazards including those identified in the appropriate Safety Data
Sheet (SDS) for this product/material as provided by the manufacturer.
1.4 The following safety hazard caveat pertains only to the test methods portion, Section 6 of this specification. This standard
does not purport to address all of the safety concerns, if any, associated with its use. It is the responsibility of the user of this
standard to become familiar with all hazards including those identified in the appropriate Safety Data Sheet (SDS) for this
product/material as provided by the manufacturer, to establish appropriate safety, health, and environmental practices, and
determine the applicability of regulatory limitations prior to use.
1.5 This international standard was developed in accordance with internationally recognized principles on standardization
established in the Decision on Principles for the Development of International Standards, Guides and Recommendations issued
by the World Trade Organization Technical Barriers to Trade (TBT) Committee.
2. Referenced Documents
2.1 ASTM Standards:
B476 Specification for General Requirements for Wrought Precious Metal Electrical Contact Materials
E8/E8M Test Methods for Tension Testing of Metallic Materials
E384 Test Method for Microindentation Hardness of Materials
3. Materials and Manufacture
3.1 Raw materials shall be of such quality and purity that the finished product will have the properties and characteristics
prescribed in this specification.
This specification is under the jurisdiction of ASTM Committee B02 on Nonferrous Metals and Alloys and is the direct responsibility of Subcommittee B02.05 on
Precious Metals and Electrical Contact Materials.
Current edition approved Nov. 1, 2017Nov. 1, 2021. Published November 2017December 2021. Originally approved in 1970. Last previous edition approved in 20122017
as B540 – 97 (2012).(2017). DOI: 10.1520/B0540-97R17.10.1520/B0540-21.
For referenced ASTM standards, visit the ASTM website, www.astm.org, or contact ASTM Customer Service at [e-mail]. For Annual Book of ASTM Standards
volume information, refer to the standard’s Document Summary page on the ASTM website.
Copyright © ASTM International, 100 Barr Harbor Drive, PO Box C700, West Conshohocken, PA 19428-2959. United States
B540 − 21
3.2 The material shall be finished by such operations (cold working, heat treating, annealing, turning, grinding, pickling) as are
required to produce the prescribed properties.
4. Chemical Composition
4.1 Material produced under the specification shall meet the requirements of chemical composition shown in Table 1.
5. Mechanical Properties
5.1 The contract or order may specify ultimate tensile strength, elongation, mirohardnessmicrohardness (Knoop or Vickers), or a
combination of these mechanical properties (as listed in Table 2, Table 3, and Table 4) as temper criterion. If the contract or order
does not specify a temper criterion, then the criterion for temper designation will be ultimate tensile strength and elongation.
5.1.1 Fully age-hardened temper is also known as heat-treated age-hardened or as age-hardened.
5.1.2 Partially age-hardened temper (where higher material ductility is retained due to either lower temperature or time of aging,
or both) is also known as ductile heat-treated age-hardened or as ductile-hardened.
6. Test Methods
6.1 Test methods shall be in accordance with Specification B476.
6.1.1 Knoop hardness tests shall be in accordance with Test Method E384. Material 0.005 in. (0.13 mm) in thickness (diameter)
and larger shall be tested using a 100-g indenter load. Material less than 0.005 in. (0.13 mm) in thickness (diameter) shall be tested
using a 50-g indenter load. A minimum of five hardness indentations shall be made on each specimen. All indentations shall be
made so that the long axis of the indenter is parallel to the rolling or drawing direction of the material. The hardness value reported
shall be the average of the five indentations.
6.1.2 All tension test specimens shall be full cross-section size when practical (see Test Methods E8/E8M).
...